1. Field of the Invention
The present invention is directed to a printer or copier device for performance-adapted, monochrome and/or chromatic, single-sided or both-sided printing of a recording medium.
2. Description of the Related Art
In electrophotographic color printers having high printing quality as disclosed, for example, by European Patent Document EP-A1-0 629 931, there is the problem that the same length of time is always required for producing a printed page given both a monochrome printing mode as well as given a chromatic printing mode. This means that was is referred to as the performance, i.e. the speed efficiency of the printer, is based on full color printing. When such a printer is utilized in a mixed printing operation, then it is usually the monochrome printing that occurs. Given electrophotographic high-performance printing with 200 pages/minute or higher, the print jobs to be processed contain a majority of monochrome printouts. Only a small portion of the print job is chromatic. Thus, for example, it can occur that a plurality of black-and-white successive pages are printed within a print job and that a full color image must then be printed, for example when producing a brochure. When the standard color printing devices are utilized for production of such a brochure, then they are relatively slow, since, as already stated, the printing performance is based on the color printing performance. Such color printer devices are also complicated and cost-intensive and inefficiently utilized for mixed operation.
Color printer devices with which single-color or two-color can be printed at high speed are disclosed, for example, by U.S. Pat. No. 5,526,107. In the known color printer device, continuous form paper is supplied to a transfer printing location of a photoconductive cylinder that comprises respective electrophotographic units for producing differently colored toner images on two surfaces. The continuous form paper is printed with a first color on the front side at the transfer printing location, the continuous form paper is subsequently deflected and supplied to a printing location at the same photoconductive cylinder lying opposite the transfer printing location and is printed on the backside of the paper.
German Patent Document A-176 18324 also discloses that color printing be performed in that a plurality of developer stations allocated to the individual color separations of the color image are arranged along a photoconductor. The developer stations can be individually mechanically activated, namely in that they are brought into mechanical contact with the photoconductor band. For producing color printing, individual color separations are generated on the photoconductor band and are then transferred onto a collector in the form of an intermediate transfer drum. This intermediate transfer drum then transfers the full color image that has arisen by the superimposition onto a single page.
It is also known to employ a transfer band instead of the transfer cylinder, as disclosed by European Patent Document A2-0 320 995.
What all known color printer devices have in common is that their performance is based on the color printing speed and that the printer devices are therefore uneconomical to utilize for mixed operation.